I have a 1984 Johnson 115HP outboard and i just received the new gaskets for the cylinder head covers(water jacket). My question is do i need to use a gasket sealer or no and if i do what should i use?
I work at an engine rebuilders. When I rebuild an engine I always use Spray Tack. I think you can find it at any autoparts store. It can help to stop those pesky little water leaks around all gaskets. Especially if you don't have the heads and block surfaced before reinstallation. We never had any complaints.
These newer head gaskets do not require a sealant. It is not a problem if you choose to use it. Make sure you retorque the head bolts after the engine goes through a couple of heat/cool cycles.